• Journal of Broadcast Engineering
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• v.11 no.3 s.32
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• pp.349-362
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• 2006

There are several data broadcasting standards that the developers should apply when develops any interactive digital TV contents. In Korea, we adopts ACAP(Advanced Common Application Platform) as terrestrial data broadcasting standard, MHP(Multimedia Home Platform) fur satellite data broadcasting and OCAP(OpenCable Application Platform) for cable data broadcasting. Therefore, content providers must develop different applications which suited for different standards - even if the application is exactly same. This is waste of time and energy. This paper suggests a solution to solve this problem among different broadcasting platforms - MHP, OCAP and ACAP. We compared these specifications, and found out what APIs are typically used far applications. Then we designed XML file structures that can be used to define contents of applications. We also implemented an authoring tool which automatically generates XML files by interaction with users. This paper also ascertains Xlet applications, produced by the authoring tool, works properly on each different data broadcasting standard - MHP, OCAP and ACAP.

• Smart Structures and Systems
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• v.25 no.4
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• pp.487-499
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• 2020

This paper proposes a novel approach to model updating for a large-scale cable-stayed bridge based on ambient vibration tests coupled with a hybrid metaheuristic search algorithm. Vibration measurements are carried out under excitation sources of passing vehicles and wind. Based on the measured structural dynamic characteristics, a finite element (FE) model is updated. For long-span bridges, ambient vibration test (AVT) is the most effective vibration testing technique because ambient excitation is freely available, whereas a forced vibration test (FVT) requires considerable efforts to install actuators such as shakers to produce measurable responses. Particle swarm optimization (PSO) is a famous metaheuristic algorithm applied successfully in numerous fields over the last decades. However, PSO has big drawbacks that may decrease its efficiency in tackling the optimization problems. A possible drawback of PSO is premature convergence leading to low convergence level, particularly in complicated multi-peak search issues. On the other hand, PSO not only depends crucially on the quality of initial populations, but also it is impossible to improve the quality of new generations. If the positions of initial particles are far from the global best, it may be difficult to seek the best solution. To overcome the drawbacks of PSO, we propose a hybrid algorithm combining GA with an improved PSO (HGAIPSO). Two striking characteristics of HGAIPSO are briefly described as follows: (1) because of possessing crossover and mutation operators, GA is applied to generate the initial elite populations and (2) those populations are then employed to seek the best solution based on the global search capacity of IPSO that can tackle the problem of premature convergence of PSO. The results show that HGAIPSO not only identifies uncertain parameters of the considered bridge accurately, but also outperforms than PSO, improved PSO (IPSO), and a combination of GA and PSO (HGAPSO) in terms of convergence level and accuracy.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.6
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• pp.709-717
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• 2002

A new multi constant modulus algorithm (MCMA) for a blind decision feedback equalizer is proposed. In order to avoid the error propagation problem in the conventional DFE structure, Feed-Back Filter coefficients are updated only after Feed-Forward Filter coefficients are sufficiently converged to the steady state. Therefore, it has the problem of slow convergence speed characteristics. To overcome this drawback, the proposed MCMA algorithm uses not only new cost function considering the minimum distance between the received signal and the representative value containing the statistical characteristics of the transmitted signal, but also adaptive step-size according to the equalizer outputs to fast convergence speed of FBF. Simulations were carried out under the certified communication channel environment to evaluate a performance of the proposed equalizer. The simulation results show that the proposed equalizer has an improved convergence and SER performance compared with previous methods. The proposed techniques offer the possibility of practical equalization for cable modem and terrestrial HDTV broadcast (using 8-VSB or 64-QAM) applications.

• Journal of Advanced Navigation Technology
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• v.18 no.5
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• pp.445-454
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• 2014

In this paper, we introduce measures designed content for RTCA DO-160 F, Section 22 tests performed to verify the effects of indirect lightning and testing process of the test was carried out in the multi-purpose display certification process. This is referred to as indirect effects of lightning capability of an aircraft having electrical electronic equipment failure or damage to bring lightning induced voltages. In order to protect the avionics from lightning indirect effects of these aircraft are analyzing the effects of lightning strikes on aircraft and aircraft systems and interior design needs protection against the threat on their part. In this paper, we introduce RTCA DO-160 F, component selection process according to Section 22 category selection method and the selected level for determining the level of such measures for protection against lightning of multipurpose display for this aircraft. It also introduces the actual test process to confirm that the designed effectiveness of the selected part. We expect a good example of the lightning planned for future development of measures designed avionics through each step of the process introduced this.

• Journal of the Korean Geotechnical Society
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• v.22 no.3
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• pp.37-43
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• 2006

An analytical solution method capable of determining the geometric configuration and developed tensile forces of mooring lines associated with fixed plate/pile or drag anchors has been developed. The solution method, satisfying complete equilibrium conditions, is capable of analyzing multi-segmented mooring lines that can consist of either chains, cables, or synthetic wires embedded in layered seafloor soils. The solution method utilizes a systematic iterative search method based on specific boundary conditions. This paper describes the principles associated with the development of the solution for the mooring line analysis. Comparisons of predictions with results from a series of field tests of mooring lines on various types of drag anchors are also described. Comparisons include the tension in anchor, the length of mooring line on the bottom, and the angle of mooring line at the water surface buoy. The results indicate that the analytical solution method is capable of predicting the behavior of mooring lines with high degree of accuracy.

• Geophysics and Geophysical Exploration
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• v.7 no.4
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• pp.251-255
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• 2004

Electric cables such as multi-interphone cables and ribbon cab]os are commonly used for data aquisition in the DC resistivity survey. In general, electromagnetic induction may occur in the electric cables when electric current flows through them. In case of using multi-interphone cables in the DC resistivity survey, electromagnetic induction could take place due to the entangled wires of the multi-interphone cables, when the current flows through them. Then, the electromagnetic induction may cause measured DC resistivity data to be distorted. In this study, a monitoring system with PXI (PCI Extention for Instrumentation) was constructed to examine signal distortion on the DC resistivity data, attributed to the electromagnetic induction. Common electric cables used in the DC resistivity survey were tested to observe the waveforms of the electric voltages. The waveforms measured were compared to examine signal distortion due to the electromagnetic induction. The results may provide information on the resistivity data obtained using different electric cables in the DC resistivity survey. The distortion of waveforms attributed to the electromagnetic induction wat not observed when using ribbon cables for DC resistivity data aquisition, while the distortion were observed when using multi-interphone. Therefore, the ribbon cables provide better quality of data than other cables in the DC resistivity data aquisition.

• Journal of the Korean Electrochemical Society
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• v.13 no.4
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• pp.240-245
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• 2010

This work explored the catalytic effect of Pt in multi-wall carbon nanotube and poly-pyrrole conductive polymer electrocatalysts (Pt/PPy/MWCNT). A home-made Pt/PPy/MWCNT catalyst was first evaluated by comparing its electrochemical active surface area (ESA) with E-Tek commercial catalysts by cyclic voltammetry in $H_2SO_4$ solution. Then, the methanol oxidation currents of Pt/PPy/MWCNT and the hydrogen peaks in $H_2SO_4$ solution were serially measured with microporous electrode. This provided the current density of methanol oxidation based on the ESA, allowing a quantitative comparison of catalytic activity. The current densities were also measured for Pt/C catalysts of E-Tek and Tanaka Precious Metal Co. The current densities for the different catalysts were similar, implying that catalytic activity depended directly on the ESA rather than charge transfer or electronic conductivity.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.192-196
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• 2010

Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. The strength of the PLC has no more additional wiring work. PLC has also possible to high quality data transmission with currently electrical cable. It has a various strong point campare with existing wire and wireless communication technologies. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. The video function was used for the VEDEO TEST GENERATOR in order to a property valuation. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal. It can be possible to have HD class Media service through the PLC.

• Smart Structures and Systems
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• v.22 no.3
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• pp.359-368
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• 2018

A method is proposed for the identification of instantaneous frequencies (IFs) in time-varying structures. The proposed method combines a maximum gradient algorithm and a smoothing operation. The maximum gradient algorithm is designed to extract the wavelet ridges of response signals. The smoothing operation, based on a polynomial curve fitting algorithm and a threshold method, is employed to reduce the effects of random noises. To verify the effectiveness and accuracy of the proposed method, a numerical example of a signal with two frequency modulated components is investigated and an experimental test on a steel cable with time-varying tensions is also conducted. The results demonstrate that the proposed method can extract IFs from the noisy multi-component signals and practical response signals successfully. In addition, the proposed method can provide a better IF identification results than the standard synchrosqueezing wavelet transform.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3111-3122
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• 1997

Since the advent of an information era, the traffic of communication has been remarkably increasing and the information service has gradually become speedy and popular. With these trends, it is necessary to extend the utilization of existing twist pair cables for PSTN(Public Switched Telephone Network) to provide high speed data services for telephone subscribers, In this paper, we have studied on a structure of discrete multi-tone ADSL(Asymmetric Digital Subscriber Lines) system which can support high speed multimedia service using a twist pair cable, and analyzed the transmission performance by computer simulations.